Fatal trap 18: integer divide fault while in kernel mode
cpuid = 3; lapic id = 3
instruction pointer	= 0x8:0xffffffff80911d57
stack pointer	        = 0x10:0xfffff8011a7bb3c0
frame pointer	        = 0x10:0xfffff8011a7bb6b0
code segment		= base 0x0, limit 0xfffff, type 0x1b
			= DPL 1, pres 1, long 1, def32 0, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= 1138
current thread          = pri 6 
kernel: type 18 trap, code=0

CPU3 stopping CPUs: 0x00000037
 stopped
Stopped at      ffs_mount+0x627:        idivl   %ecx,%eax
db> 

[--- ffs_reload (inlined into ffs_mount) adopting re-read fs_fsize=0 ---
     howmany(fs->fs_cssize, fs->fs_fsize) at ffs_vfsops.c:515 div-by-zero.
     Trigger: mount -o ro crafted image; craft fs_fsize=0 on backing
     device; mount(2) MNT_UPDATE|MNT_RELOAD|MNT_RDONLY. ---]